We have already been years on our build and are still on phase 1 of probably 8, many times I've considered giving up.
the only reason we haven't is because we live next door and I couldn't stand seeing someone else doing it.
We are a totally DIY self build and we've made mistakes, had bereavements, job losses and the consequent money issues.
Do what is right for you, but consider how you would feel if you sold up, if it's total relief then do that, if it will be regret then battle on.
You can always sell up in the future, but won't be able to buy back once you've done it.
Good luck with whatever you decide and I hope it works out for you.
Feel free to reach out to the BH community and maybe find someone local who you can physically visit and see their progress / finished results.
By the way, we are in our 60's so you are not old 🙂