Just my $.02. for my eyes, retirement physical health and typical local schools. Obviously your's may be different. Eyesight for specialty work often calls for special gear. RDS? Maybe. But not for me. I would personally go with work bifocals with the readers up top at about 12-14mm tall.
I figure I could gain/keep more of my skill if I concentrated on just one platform. For me that would be a pistol and not a pistol/rifle. See below.
I could run to my rifle in the car and then run to the problem. But I figure I would just run to my problem, skipping the rifle in the car. Less people shot.
While there are certainly some long shots to be had at schools. Classrooms, dark hallways, looked at with old eyes and all those kids, teachers, etc I figure the job will require running to the problem more than shooting it from afar.
So for me (just maybe for you?) I figure a new set of glasses that have mid height vs top attach ear stems. Squeeze in the top bifocals. I figure starting and continuing to work more distance into the weekly shooting working up to 50 yards in the first 6mos/year. I figure adding/staying/getting into shape to run. Adding in running and shooting to the weekly training.
For me that would be the easiest, keep it simple routine.
ETA: If you've been shooting Glock for so long, concentrating on that would also probably gain you a faster improvement in distance shooting. Or at least that is where I would start. You can always change that later. But again I'm of the opinion that distance is important but not the most important.