I too have a dedicated trainer bike. I used to not and just removed it on and off as needed. Then I got a new road bike and then used the old bike. I did take off some unneeded parts from that bike and used on other projects. Trainer bikes don’t need brakes and stuff like that. Not necessary though. It’s a luxury to have a full time trainer bike IMO. But I would go back now either.
If funds are tight watch used bikes and find a decent used bike. It just has to fit and have a good base.
Good luck