I think the LD-16 (Wittur product is your best bet as they are engineered specifically as direct replacements for the old Miami Elevator/Early TK door equipment. I'm also a grinch of harmonic operators. They are just too outdated and have too many moving parts. If you wanna go cheaper, GAL has a direct replacement linear product where the only thing you'll need to replace is the operator itself. You will be able to reuse other existing components, such as the skate and hanger roller/tracks. It's called OMNI. Just like LD-16, there's no limit cams/switches to deal with. If you've been having difficulties getting parts from VE/TKE, the GAL product is your best bet. It might be easier to source parts.
LInk:
https://www.gal.com/wp-content/uploads/2023/08/GAL-MONXT-OMNI-Telescopic-Linear-Operator.pdfYou could also get a Glide-A (or P) from Otis.