Pretty convenient theory if you are Right leaning
The first Trump impeachment was easy to see from the get go - if you were against him, you said at the end of the call Trump was trying to dig up dirt to use on a political rival. If you were for him, you said he was trying to dig up dirt on 2016 election corruption.
It's on the accusers to prove intent, and it fell short if you watched the hearing. But it didn't stop the Democrats from 100% voting on party lines.
As for the Republicans, it's not any secret or conspiracy that red congressmen in blue area would be vulnerable if they vote to impeach Biden. It's just a fact, and has been shown in local polls.
Impeachment should not be used for political purposes. That was not it's intent, but the Democrats opened up this box, and anyone paying attention knew it would come back around.