I’m not sure if this is the right place to post this, so please direct me if there is a more appropriate subreddit.

Basically, I would like to get a personal trainer, but I have no idea how to go about it.

Some context:

I’ve been weightlifting/training for 10 years now and have mainly taught myself everything I know through years of YouTube, online articles, etc. however, I’ve realised my progress is not as good as it should be and physique remains amateur.

What is the best way to go about getting a PT? Should I just use the gym’s PTs because they are already there (I train at a leisure centre in the UK if that is relevant?)

If I get an outside PT, will they be able to enter the gym with me to help with form and technique, etc? (I presume not, if so how do outside PTs train with their clients?)

An online trainer I am skeptical about for some reason (I guess it’s because they can’t see me train and my body irl)

Also, in the lower half of my body, I am all messed up as (I think) I have very tight/short hip flexors (and associated muscles around the hips and groin) which I can’t seem to stretch out. I suffer from knee pain a lot and I think this is due to bad form and tight/short muscles in various places in my lower half. (this is why I believe I need to see a PT irl so they can actually diagnose wtf is wrong with me because I can only guess from my uneducated eye.) also, could a PT even deal with this particular issue or would I need a physio therapist or yoga person or something?

Thanks in advance for your advice.