When mine were little, I assigned an older child to watch the toddlers while I worked with another older child. We would rotate who was helping with littles and who was working with Mom.
When I needed to work with my older kids in a group, I tried to have an activity for the toddler to do very close by.
They were often in a highchair right at the table with us. That was a great time to give them sensory toys to keep them engaged.
And remember this is a season and it really doesn't last forever. Give yourself a lot of grace and expect interruptions.
Keep it simple.
A muffin cup with colorful pompoms and tweezers or tongs.
A simple shape sorter