Then everytime you switch between planes you have to retrim the plane as you will loose the trim. And if you want to stick to the hobby your best move will be get a better radio. As you will need it soon or later.

If money is an issue, then move all your radio gear from trainer to 4*, once you start flying it you will not want to fly the trainer. If money is not issue get a radio with model memmory and trim memmory, preferbly digital trim lever so that you don't have to remember to save the trim. Which I always forgot.

But before going to 4* get most out of your Alpha, don't be emberessed from flying trainer, at least I was and wanted to fly a better plane.
I finshed and flew 4* after 100 flights with my trainer and there is no rush, there are hundreds of beatiful planes out there, you will fly them eventually not all but some.

So my advice is fly the trainer as much as you can then move radio to 4* and foirget about the trainer. Unless something bad happens.

For engine, I flew my 4*40 with 46FX and flys great.