My equine dentist suggested Leigh chop senior as a hayledge replacer for my golden oldie. She also has 3 feeds a day with fast fibre and calm and condition in it
My oldie has poor teeth and is on high fibre cubes which are soaked into a mash. She can still manage soaked hay and has that too so she is not on a full replacement ration.
If you go down this route check carefully the feed content as hay replacers vary a lot between brands. You still want low sugar and starch especially when feeding as a hay replacer.
There's a zillion alternatives and the answer will depend on the individual horse, the owners purse, time, management etc etc etc. I'd ring your favourite feed company helpline and discuss with them. I've found D&H excellent because they work closely with Prof Knottenbelt and can provide tailored diets for problem horses x
You could try soaked grass pellets (I've found the Graze On ones the best) you could either soak them just enough to crumble or make them into a soup. I wouldn't like to use the Alfa pellets for an oldie myself.