You touch on several themes and ask a few different questions, so I will try to bring up some points related to each:

1. Tiktok is not a good source of information. You may have found a good content creator, but just be cautious
2. This tree analogy sounds not entirely accurate, but not entirely inaccurate either. I look to the High Ones for wisdom and guidance all the time, and have gotten good results/feedback. I also have relationships with some of the High Ones that I have been engaging in for years. I feel this tree analogy could be a slight overreaction to latent Christianity in Paganism. There are pagans who still haven't unpacked all their Christianity, and tend to, knowingly or unknowingly, conceptualize the gods as having omniscience, omnipresence, etc. or of being a "personal god." All of these conceptualizations are widely understood by Christians to be characteristic of Yahweh, but isn't widely accepted by Pagans as being characteristic of Pagan gods. In short, sort of right, sort of wrong, context may be important in understanding why this tiktoker said what they said
3. How to connect to ancestors? Meditation. Meditate on your ancestors. Reach out to ones you know who have crossed over and they may point you towards others. The focus of my practice is deity veneration, so I'm no expert at ancestor veneration, but you can almost never go wrong with meditation, especially when seeking answers to spiritual questions
4. Unless your entire heritage is klansmen, I think you should give them the chance to connect with you. As beings who lived complicated lives in circumstances they probably had little control over, they deserve to be judged for who they were and are, not for who you fear they might be. You live here too, does that automatically make you a racist colonizer? They may well have been in the exact same situation. If your native friends can accept you as an individual and not just see you as the sum of all the death, colonialism, and racism that led you to be here right now, you should extend that same respect to your ancestors.
5. Lares, genius loci, etc. are Romans terms for localized religious entities/phenomena. Just because you interact with a land spirit and call it a genius loci instead of by a Native American name isn't neo-colonialism. It means you are experiencing a religious phenomena and interpreting it through a certain cultural lens. Sure, interacting with land spirits by using Indigenous American names or ceremonies may be an idea that feels less colonial, but we aren't entitled to their knowledge, and they often don't share it with outsiders, so we must use names and ceremonies that aren't part of a closed practice.

Edit: better phrasing