Solo CK pool has only ever found 11 blocks ….
8 of them were in the last 6 months👀
Discussion
292 blocks when you look at all the data on mempool.space 
I wonder why on mine it was showing way different numbers ??hmmm
I was looking at 6 months and “all”
because mempool.space has miner data for the past 11 years, you have not been running your instance of mempool that long to capture the miner data.
It looks like it populates it over time, there is a rescan tool that you could use, but try putting block 321919 in your search bar. It was a block found by solo ck pool 11 years ago. You should see it and I think it will add it to your solo ck pool blocks.
What is an instance again??