Medalist

both are about someone who got a late start in their respective sports, but have the passion and talent to make up for it. both are heartfelt, inspiring, thrilling to watch, and have amazing characters.  

Both shows are about a veteran athlete who has been pushed out of their sport discovering a young girl talent in the same sport and choose to mentor her. Further, both shows heavily feature the characters dealing with their personal struggles outside their given sports and what they have to do to live the way they truly want to. 

Both shows seem comprised of flimsy plots that constantly and sporadically get halted to torture children. Eight times out of ten it does not meaningfully impact or at all progress the story. Both shows feature color palates that confuse the brain - like the saturation is off or something you cannot quite place. Medalist is a modern-set sports anime, whereas Made in Abyss is a fantasy adventure setting. They both have similarly sized casts. Made in Abyss is longer, having multiple installments to the franchise, and I would say it gets better as it progresses (as of writing this). 

Both anime have an older main character who wants to achieve his dream. They focus on motivation, perseverance, and the pursuit of becoming the best version of oneself despite the harsh reality. 

This anime also explores themes of overcoming oneself in situations where those around you are more talented in a certain area. 

The two series have the same scriptwriter (Jukki Hanada of Euphonium, YoriMoii and Stein's Gate fame). Both series use a mixture of constantly alternating drama and comedy. Both titles are super popular in Japan but less known in the West. Both use 3D-CGI for animation (Medalist extensively, Girls Band Cry almost exclusively). Both series use motion-capturing as input for the CGI process, Medalist for the skating perfomances, GBC during the rock concert scenes. Both have great OP / ED and OST music.