Same age gap here. Albeit mine are a year on now. Last winter was tough.
I know you say indoor but my sanity was walking. Pram or sling, a bucket, toddler, snow suit, off we go. They carry the bucket, collect stuff, whatever there is. Leaves, cones, apples, etc etc. every single morning.
Tire them out. Lunch then nap.
Afternoons, a little telly time, another big walk, washing stuff like you say.
Things like
Water pens and mat or books were popular.
Books
Emptying a cupboard all over the floor.
Helping
with jobs. So give them a baby wipe, clean stuff. Carry some washing for you.
It yes, essentially I walked them until they were able to play more!