Indeed. If a few high profile teams boycotts it, then the rest would follow.

Better yet, if Germany, Italy and a few others offered to host a tournament for the qualified teams (with FIFA blessing or not) maybe others would join?

This is how the NHL should have treated the Olympic ice hockey tournament in China: rather than boycotting they should have simply played the games in Taiwan to make a point. Whether they would count as Olympic matches would make no difference. The kick in the groin to Chinese and Qatari bigwigs would be glorious. Millions in bribes wasted .

Teams pulling out would most definitely make a difference. It does make you wonder why the players/managers do not get together and... strike.

Few national teams and players would dare to boycott it. National careers are short with few possibilities for success ( one of the advantages of a World Cup every two years would be that more teams and players could have success), and just playing for the national team, let alone at the biggest competition in sport there is, is a source of pride.

The popular YouTube football channel Fifo Football made a video on whether national teams might boycott the World Cup 2022:

Will Countries Boycott The Qatar World Cup? https://youtube.com/watch?v=7KL9LExsPLI

(TL;DR: No)