Can I go from Warsaw to Lisbon by bus without border check? [closed]

Taking the bus is not a good way to avoid controls. Wether you're worried about the unpleasantness or inconvenience of controls or if you're worried you're bending the rules of a visa, taking the bus is probably not the best mode of travel, it seems likely that you'll experience a higher level of scrutiny by taking the bus than other modes.

In this TV report about human trafficking (in German) you'll notice how the German police systematically stop buses near the border. The first group people they stop have valid Lithuanian tourist visas, still they're hauled off the bus and into a police station where they're deemed to be abusing the visas because they only stayed in Lithuania for one day and they aren't carrying cash when the stated purpose of their tourist visa was to buy a used car.

Even at the height of the open borders before the influx of refugees in 2015, scheduled buses were targeted for "random" internal controls inside the Schengen area. During this time I once crossed Germany by bus: we were stopped four separate times in one night by various German police for "random" passport checks. Across the EU, I've experienced the same "random" checks more often when travelling by bus that by any other mode. I've experienced this Czechia, Austria, Germany, France and Belgium.

France has introduced spot checks at the land border, and German police perform internal foreigner checks on buses fairly often.

Just fly! You will definitely not face any border checks that way, and if not taking Ryanair, easyJet or Wizz and only having hand luggage, you will not normally be asked for any ID by check-in staff.