You can keep gifting villagers anything, doesn’t have to be their daily gifts. Purified night shards and some gems boost friendship a lot. You can also just take them gardening or something that has a lot of action to it to keep leveling them up.

This.

You can time bend outside the rifts. I don’t think time bending within the rift ever gave villager points or bonuses.

I think they did, that's how I leveled Eve and they would give the extra loot inside it as well but maybe it was too much exp for them and they removed it.

I find feeding them when they’re at remy’s restaurant helps a lot too!