What you can do will depend on lots of things.
Can he follow adult led tasks? Can he sustain attention? If not, how long does his attention last? Can he play games involving multiple people? Is he easily frustrated when he doesn't get things right? Can he make marks and trace shapes? Can he colour mostly in the lines? Can he hold a pen?
There are lots of barriers that can be developmental that aren't picked up in nursery, but rather assessed as still developing because their approaches don't meet the needs of all children in all areas.
My son is academically delayed, though he also has a significant speech delay (almost caught up now though age 6), and even though he could understand language perfectly he couldn't practice reading, writing, sitting with age appropriate workbooks, listening to stories, because he couldn't do any of the above so our foundation building skills looked a lot different and we had to tackle his attention, being able to share, being able to follow adult led tasks, not giving up when things don't go right the first time etc...
Once he was in reception he started catching up but they did assess what interventions they could put in place, and there were two big ones, one called jump around for sensory and motor integration, which was fun for him but also worked on the key skills of being able to follow adult led tasks, and then music interaction which focused on taking turns, listening, beats, following a routine etc.
We then found tasks at home to replicate this.
Due to my sons needs he ended up resitting reception because for the first year of reception he was focused on building these skills rather than phonics and maths, but in the second year he was working at the same level as many of them.
Once he could follow adult led tasks we bought additional resources for at home, like the edurino sets which we specifically only bought one character at a time with to focus on main areas of learning and prevent him being able to switch out to ones he found "easier" to avoid having to put in the work.
We also have reading hour, which is before tea time, not before bed, because otherwise he would be too tired to absorb anything.
We do use screen time but we stick to things like yakka dee, numberblocks, miss apple etc.
We also have a toniebox for when we don't want screen time and have run out of words for the day, and there are some fun educational tonies you can get.
So in short you need to find out why your son is finding it hard to catch up before you can help him catch up.