So current ultra nationalist government in Poland wants to return to good old days of GDL and Make Poland Great Again, but it is too scary to go into open confrontation against Russian army again so clandestine work using Lithuanian and Belarusian stooges is the order of the day. There is no surprise that so called Belarusian opposition information center "NEXTA", which provides all these horror videos and coordinate "spontaneous" protests and riots is located in Poland.
I don't know what you are talking about. The so-called "ultra nationalist government" is not as nationalist as some idiots make you believe. It relies on giving out social handouts that are the biggest ones in Poland's history.
The idea about using Lithuanian stooges was probably taken out of your hat, as Lithuania is a fully independent country whose policy towards Russia is MUCH harsher than the Polish one. It's primarily Lithuania who kickstarts any random actions against Russia, but Poland is much bigger and populous, so the latter's actions are more visible. It was the current Lithuanian government who started pushing for improving relations with Poland, as they were rather bad between the times when Lithuania regained independence and 2015. The current Polish government started trolling the Lithuanians, telling them in a totally undiplomatic way that Lithuania needs Poland much more than Poland needs Lithuania and Poland can still be independent without an independent Lithuania, but it's not the case the way round. The Lithuanians got the message and started warming up relations with Poland immediately.
It was the Lithuanian Foreign Minister who referred to Lukashenko as the former Belarusian president right after the "elections", while no Polish politician has said so yet.
Regarding Poland's stance towards Belarus, you are just plainly wrong. It was the previous, so-called democratic Polish government who was much more active in supporting the democratic opposition in Belarus, while the current government has significantly reduced it. A few Belarusian pro-democratic activists have been arrested in the last couple of years in Poland and extradited to Belarus. Probably, it's something that you cannot read about in your country, but actions speak better than words. The opposition gave the Polish government a lot of sh1t due to such a behaviour, but the answer has always been the same: "we just follow international procedures and if somebody is accused of a fraud, we have to extradite them". Regarding "Nexta", its influence is pale comparing to what the previous government was doing in order to support the democratic opposition in Belarus. The current government totally changed the tactics and its stance was warming up relations with Lukashenko instead of giving him more sh1t, so a lot of projects aimed at supporting the opposition in Belarus have been cut or totally scrapped.
It has been working very well until now, as Lukashenko got the message and became bolder when it comes to dealing with Russia. He refused to open a few Russian military bases in Belarus, some of them close to the Polish border. Numerous times, Polish officials were the only EU officials who wanted to talk to him. There were a few commemorative events in Poland where he was invited, while Putin was ignored. He also proposed Poland and Ukraine to deepen the rivers between the Black Sea and western Belarus in order to become less dependent on Russia.
In other words, Putin's failure to incorporate Belarus has much to do with Polish diplomacy and good relations with Lukashenko that have just recently changed after the Polish government supported the Belarusian opposition officially.
Regarding Poland's nationalistic stance, again, you don't know what you are talking about. Polish government says something different purely for domestic purposes, but does something totally opposite. Let's say it refused to take 7000 Muslim refugees in 2015, making the "Muslim" the keyword, while 35,000-40,000+ Muslims have been getting a permanent residence in Poland every year since the current government came to power. The immigration from Muslim counties has never been so high, but they come to Poland legally. Poland issues more work visas than any EU country every year, so the number of foreigners from all over the world has increased significantly. There are about 2 millions Ukrainians living in Poland and a few hundred of thousands Belarusians. Some of them get grants from the government to get a higher education in Poland or are exempt from fees.
Regarding Ukraine, the current government is harsher towards it comparing to the previous one. A few Ukrainian politicians were banned from entering the EU after the Polish government discovered they supported UPA too much. When a Russian separatist from Donetsk opened a company in Poland and imported a sh1tload of coal, Ukraine started raising the issue to the Polish government. The latter said the guy is not on any sanction list and did not violate any Polish law, giving the Ukrainians a hint to fvck off.
Also, import of coal from Russia is at all times high, making Polish miners extremely upset.
So, it's not about making Poland great again, but to counter the Russian influence and having both Belarus and Ukraine as a buffer, exactly as they are now. Poland's goal is not to take these countries over or make them Polish colonies. Unlike Russia, Poland does not aim at taking these countries' industry or making them more dependent on Poland.
Poland just wants Belarus to be neutral, while Russia clearly pushes for taking it over. That's the key difference. It was Putin who proposed Luka to merge Belarus into Russia a make the latter a PM.