OK, here's where I am

I did some testing today with my neighbor's boat. My head unit works fine, I hooked it up to his transducers and got a depth reading instantly. I can replace mine for about $300-$350 and be back in business. The issue is, as I mentioned in the other post, I have never really liked this Helix 7. I would have bought the Lowrance off the hop if I had known I was going to go with the MG Xi3 TM. I got it during Covid because it was the only one in stock and have really come to like it. I am trying to figure out if the new Eagle units are compatible with my TM like the Elite units are. I also found a Simrad unit that will work with my TM as well. If the Eagle units are compatible then I can get a larger screen, which is more important to me than upgrading to live imaged in the future. I am a 100% fair weather fisherman and I just don't need that much tech to have a good trip. I think my question is; Would my HB head unit be worth anything to anyone? Not to re-coup costs but to satiate my need to not see this unit go to waste.

Here are the units I am looking at,

Lowrance Eagle 9 Fish Finder/Chartplotter with TripleShot HD Transducer | Bass Pro Shops

Lowrance Elite FS 7 Fish Finder/Chartplotter Combo | Bass Pro Shops

SIMRAD GO9 XSE Chartplotter with Active Imaging 3-in-1 Sonar and C-MAP DISCOVER Chart | Bass Pro Shops

The only reason Garmin is not on the list is that they don't jive with my TM either lol.