I used to keep stocks of “balilla x solana”, arborio (or similar) as well as Japonica rice, then I eventually realised that the kind of Japonica rice I buy does everything I need it to.
The one I’m using now is grown in Italy, doesn’t say what kind it is but it’s similar to Akita Komachi and Koshihikari, might be a hybrid.
All of the kinds I’ve mentioned are quite robust as short grain rice varieties. There’s a popular paella rice in Spain called “senia” (I seem to remember that being the rice of the La Fallera and SOS brands, which are big in Valencia) but it is very pernickety, if you cook it for too long it loses its integrity (se pasa - it “goes over”) so you really need to know what you’re doing. A big part of why “bomba” rice is so prized is that it’s much harder for it to over cook in this way, the price one pays is that it needs far more stock so it’s harder to make it taste great with as few ingredients as the tricky senia rice needs. Balilla x Solana (you might know it as Calasparra rice) needs a little more stock than Senia but not nearly as much as the Bomba rice and doesn’t “go over”/“unravel” very easily.
I’m not the only Spaniard to discover that certain Japanese rice varieties are an acceptable substitute for Spanish kinds. In the States, a good all rounder is Kokuho Rose - although I admit that I never used it for risotto, it does make excellent arroces. Just don’t rinse it first for Mediterranean dishes.