I second the library. Our has a story time 2 days a week and a STEAM program for ages 3-7 on Fridays I’ve been meaning to take my 3 year old too. We also have my oldest in gymnastics and swimming. The youngest is in swimming and will be starting gymnastics soon. But those do cost money.
Look into YT channels for kids yoga. You can do mommy and me yoga together. It really depends on how active your LO is and what their interests are. Do they like arts and crafts? Try incorporating them into "helping" with chores. My son loves using the duster around the house while I'm tidying up.
We recently started making small things together like chopping a banana or spreading peanut butter on bread. It takes longer to make snack-wise but it's a fun mess.
Pinterest helps! I’m in groups on FB for ideas and I literally just go outside every day. I find free events and go to the local library
How old is your child? You mentioned nursery, so I'm guessing 3-5? Definitely check your local libraries. And reach out to your local homeschooling community to see what free/low cost opportunities are available near you.
I’d speak to your health visitor - there might be free baby classes they can refer you too/ tell you about in your area. There are often also buggy walk groups and the library runs events. Lots of churches have free ‘soft play’ mornings with lots of toys out.
Get yourself some routines. I recommend writing them down and adjusting until they become second nature. If you don't like something or realize something is missing, change the routine. If you want to be like nursery, start with song time, story time, outside time, and throw in the occasional art project. It's ok for it to be boring for you. Remember, the adults at nursery also find it to be an exhausting slog much of the time. The nice thing about being at home is that you can teach your kid stuff in a patient, loving way that others won't. Teach him to make tea and healthy snacks. Teach him to read. Teach him to love nature, or music, or animals. Teach him to care for his body and environment (hello Montessori!). When you are bored, teach. Also, join a mom's group. You need people to talk to who are going through the same phase of life.
There are all kinds of things on Pinterest or Instagram. You could try your local library. They usually have programs that you can attend.