Trail marathon a month before trail 50k–bad idea?

Hi! I am starting the 50k Lvl1 plan next week for a May 21st trail 50k with just over 6000′ of climbing in my local mountains. It’ll be my first ultra. I’ve run a 14-mile trail run in the same area, and several road marathons (8 years ago) and a few 70.3s (recently). I used 80/20 plans last year to run my fastest 5k and fastest road half marathon in about ten years, so thank you so much for that!

My question is: I have the opportunity to run a trail marathon (with much less elevation gain than the 50k) exactly one month before the 50k. Is that a good idea for race tuneup, or is that asking for burnout? Would running the trail half marathon be better? Should I skip it altogether?

Thank you!