Back in 2018, when I was on vacation with my wife in New Zealand, I did a private MTB tour above Lake Wanaka, including all of the single track “blue stuff” in the Sticky Forest. The MTB was a 29er with a drop post [You can see the bike in the photos]. I did well, except where I needed to navigate around large rocks and around tight trees (with large branches) where I had to walk some of the time. FWIW: It was on this ride that I fell in love with the drop post (and am surprised it has taken me 4 years to finally be motivated to do something about it).
If you are really not gonna get a new bike, might as well add a cheap dropper.
I did the same for my ancient hardtail last year.
Spent some time over at pinkbike’s classifieds and got a barely used KS eten for $62 shipped.
Since all new bikes are internal many people are selling off the old ones.
Don’t spend anywhere near $500 or get the best for that bike.
External should be your only choice. Just ziptie the cable along the frame.
Use a remote made for 2x on the left and it will be fine.