If you think the interest is deductible, enter it where you enter deductible interest.
If not deductible don't enter it.
So, interest subject to tracing rules, I can keep track using Form 4952 by entering manually, this I see on screen 30. Which screen do I use to keep track of excess business interest?
Do you need to? Is the trust subject to the 163(j) limit?
If you need to, keep track in Excel. As you have noticed, the trust program is not robust for entering K-1s received. (Neither are the 1065 & 1120S programs.)