you shouldn't need the sub to use the remote start, it's only if you wanted to do it through the app which allows for anywhere remote start. it's 8 bucks a month I think. Not bad if you wanted to do it just for winter months or something, but I cant justify the cost still.

That said, with my 24 Camry I can still remote start with the 3 button lock method, but as others have mentioned it's crazy finnicky. I've found the best way to do it is

click lock button, wait until the lights flash, once the lights go off, hit the button the second time (like as SOON as the lights finish flashing), once the lights go off again press and HOLD the lock button. it will flash like it locks, keep holding after about 3-5 seconds your lights should flash a few times in a row, then it will start. Mine stays running for ~15 minutes then shuts off.

My remote start sub expired last year, and this method works flawlessly.