I have a weird use case, recommendations needed!

I've been looking at CRMs and similar software for a bit without much luck, but I have a kinda unusual use case and was curious if anyone had a good direction to send me in.

Basically, I'm looking to track two different types of entities: gyms, and trainers. I don't care about collecting/storing any information about the customers who actually come in for training, just the actual gyms and the people who run the training sessions there. This needs to be able to scale to hundreds of gyms and trainers.

In terms of the features I'll need, it's actually relatively simple. I need to be able to:

• Track which trainers are associated with which gyms (this is potentially a many-to-many relationship) and generate/download simple reports about this information
• Collect an annual fee from each gym and process the payment
• Attach a signed contract to each gym (bonus if they can actually do the signing in the software/platform)
• Store basic contact information for gyms and trainers
• Use tags, categories, or some other method to track the status of each gym (e.g. "applied", "approved", "lapsed", etc) and each trainer (e.g. "applied", "in training", "training completed", etc)
• I don't mind if I have to set up the profile/account for each gym, but ideally trainers would be able to set up their own profile/account

Googling any of this sends me down an unhelpful rabbithole of dedicated gym management software, which always has a ton of features I don't want/need (scheduling, customer check-in features, etc) and also would be outrageously expensive because they seem to usually charge hundreds of dollars per facility.

Anyone have any suggestions here? Even just knowing better keywords to search would be a start!