At that age I found it so important to get out of the house every day, even just for a walk.
Try to break the day up - mornings go swimming or soft play (you go in with toddlers to the latter too), then lunch or coffee/snacks, nap for DS in pram if he will and then you have a peaceful wander around the shops/have another coffee and read a book/surf the net etc, or go home and you also have a lie down/relax in front of tv/read.
Afternoons - pop DS in a puddle suit and go to a park, feed the ducks, playground, garden, mud kitchen in your garden depending on temperatures etc. Home for some play time - bath with lots of bubbles, get a play tunnel/tent for DS or throw sheets over dining table, play with Duplo or building blocks, bake some basic biscuits and encourage him to pour and stir (messy but my DS likes doing this), ride-on vehicle in the house if space allows, etc.
Other places to visit are the library, farm parks, garden centres often have children’s play areas now plus you can have a coffee, explore playgrounds further away from your home, some museums have good facilities for children, get yourself on local Facebook groups to look for news on things to do or perhaps put a post on yourself asking for ideas for toddlers locally.
Charity shops are good for toys to try out and see if they take DS' interest without breaking the bank.