Massage Gun, RENPHO Massage Gun... https://www.amazon.co.uk/dp/B082FHY6JG?ref=ppx_pop_mob_ap_shareBig and heavy but it doesn't stall when digging in like some I've tried.
I used massage gun internals in my uni final project and compared speed (and variability), force, amplitude, battery life and weight/size of a bunch of massage guns (mainly the compact ones)Weighing these up against price, my recommendation is the Pulsio Air. It's only £65, tiny (450g), has 27kg force (theragun pro is 30kg), 14mm amplitude vs standard 10mm and claims 12hr battery life (I doubt this and but never fully tested it)Having taken it apart too, its well built(No they're not paying me haha)
Did your uni project explore whether these things actually made any difference at all?