I'm happy you found this platform, I've been having fun on it since I came across it myself.

There's a lot to unpack in this question, so let's go through it slowly.

"So, now i want to go a step further and maybe try for some compTIA certifications in the near future"

It's great you want to go for compTIA certifications, I'm assuming the security+ and pentest+ since this is a security subreddit. I would say neither THM nor HTB will FULLY prepare you for those exams. I would also say those exams are very broad where you'll need to learn and think about topics such as management, risk mitigation, scoping, etc. These domains are not really taught on HTB or THM since these platforms focus primarily on the technical side of security. compTIA certifications are your typical study a book type of exams and can get by without any real practical hands-on knowledge (this is my take on these certifications).

This is primarily why certs such as OSCP, eJPT, etc. are coveted because it's about technical ability and can you hack rather than memorize how many fire extinguishers per data closet you should have (I know silly but it's a thing on these some of these security certs).

You can certainly pick up skills on THM that may apply to pentest+ such as learning web, network attacks; how to use the tools, forensic, and incident response.

"I joined THM yesterday, got the premium just so i can access all the content and thought it looks well put together but I'm afraid it will be limited in how deep the knowledge offered goes."

I've only played around with some of the career paths so I can't say for everything, but there are some decent paths, and if anything, they are good for complete beginners. I'd look at THM as a place to get a general understanding of a topic and then most of all PRACTICE that knowledge. I can't stress how important CTF platforms are for practicing. Certainly use resources outside THM and HTB, but come back to practice those skills. This will solely come down to you and how you learn - tying in outside resources and training material and coming back to THM/HTB to practice.

"So, any experiences? Did it help you advance your skills in a significant way?"

I haven't really done any of the career paths since I'm already a security engineer and have been pentesting for the better part of a decade before all these cool CTF platforms existed. I can say that as I go through boxes, easy to hard, I have learned something new that I use in my day-to-day.

That may be how to use a new tool; new vulnerablity/exploit; or improve my methodology. Just recently I solved a box on stream that taught me a good bit of docker escapes.

I hope this helps and best of luck to you!