You might want to try and ask around the Muay Thai school and see if anyone does BJJ, you might find someone who is a purple belt or above who teaches and knows where to roll a few times a week.
I know plenty of fighters who train other disciplines at separate schools or with another group of people.
We have BJJ seminars with guests from Brazil (mundial champions, ADCC champs etc.) and people from other camps who train at our school for a while in preparation for a big fight.
The MA community is sort of like that and you don’t have to be a fighter to do this.
Good luck both styles are very rewarding and have their own dynamics and physical and mental demands.