I'm not sure if your over-valuing TT or not, because it is a strong hand. But you want to play it in a way that will maximize it's expectation. Which range of hands would you rather play TT against (1) 66+, AQ+ or (2) JJ+, AK. It's clear you would rather play agains the number 1 range. Well, by 3betting you are making it more likely that villain will have something similar to the range of hands in #2. Whereas by calling he will have something similar to range #1 (but this is obviously very opponent dependent).

Well when you call you are obviously hoping for a flop with a Ten. It's hard to tell you how you want to play the hand just based on the cards that come on the flop, turn and river, because your decision should depend on more than just that. However, of course you would rather see a flop like 2h5d9c than a flop like AhKdQd.

Another thing... You seem to be just lumping every villain you encounter at 5nl into a "donk" category. While it's true you likely won't find pros grinding it out at 5nl (don't even bring up the negreneu, Jesus, etc stuff), not every player you encounter is going to be a massive donk. If that were the case then you are saying you fall into that category, along with many other 5nl players right here on FTR. Things in poker are very situational, and one thing that can change a situation dramatically is the villain in which you are playing against. Without reads/stats, you can really only make a generic assumption. That's why reads/stats are so important. It can easily change villains UTG opening range from something like 66+, AJs+, AQo+, KQs to something similar to 22+, AT+, KJ+, QJ+ just depending on the villain.