First off, your regeneration rules require to much book keeping. You need to keep track of the pool of points for it, remember to regenerate every round, and remember how much damage was fire and acid. Your food rule is also strange, at level three you need up to 10lbs of food to keep from starving. Which also prevents you from regaining your regeneration points. You can regain these points by eating 3x as much during a short rest while taking a level of exhaustion.

Even in the two campaign types you recommend for this race the DM would need to be careful about what they did. They would need to allow you enough food to keep your regen going, and would need to resist the urge to send a pyromancer after you. Also considering the campaign types you recommend this race is just a complex mess. An evil monster campaign is often not balanced because of the monsters chosen. You would need to make a few races for this write up to be useful. A silly one shot may just have a level one Super Sayain, so this write up will most likely be dumped or heavily modified.

The class restrictions are really unneeded. You restrict the race to only 4 classes, and further restrict their subclass choice. You make the ability score decreases of the race redundent as trolls can't actually use the class. I find it odd that you avoid the Eldritch Knight and Arcan Trickster, but allow the Ranger. You appaer to want to avoid magic, but one of the only 4 classes you restrict them to is a half-caster.

The whole troll growth table seems to serve no more purpose than to say when you have all the troll from the Monster Manual.

Natural Armor is very oddly worded. The first part is fine, the second and third are weird. The second part seems to imply armor give you a bonus to your natural ac. Other forms of natrual armor, such as the Lizardfolk, are replaced by the AC of the set of armor or the unarmored defense of the Barbarian or Monk. All you need to say is this, "Your natrual armor does not stack with any other form of armor or unarmored defense. You must choose which one to use when determining your AC."

The subraces are fine, though the 1ft of burrow speed seems unneeded as you can just say the subrace is able to dig out a hole to use as a way to sleep or hunt. The sunlight sensitiveity should just have the same wording as it does within the Player's Handbook.

The background has som interesting choices. The skills make sense, other than animal handling, but tools don't make any sense. If your goal is a stupid feral monster, than it wouldn't gain a proficiency in any tool set. In equipment the tree branch should be noted as a club and not a maul. Mauls are hammers and clubs are commonly chunks of wood, some times they are just a thick branch.

Your DM information seems to imply someone playing a Troll in a party of non-monsters. This section seems to worry about balance, which shuldn't be a problem as the 2 campaign types you made this for usually have overpowered characters.

I won't go into the last part of the document, as you are explaining why you made this. Overall the rules and features don't lend themselves to balance at all, and a DM will either alter it or just drop it depending on their game.