Keep in mind that a mining farm is also a solo miner but with a higher hashrate. Also, it is not just the address that indicates this is a solo miner it is the fact that the miner is not sharing the work with other miners and the work they perform is unique (on a block that is different from every one else).
every asic within a pool does not repeat the same work as another asic. as thats just stupid inefficiency.
the difference between solo and pool. is not about if a asic is or isnt doing the same work. it is not about if the winner gets 98% or 0.00x% of a reward. its about who manages what work an asic is given.
if the work is chosen collated and distributed by a manager. then that manager is a pool.
if an asic has its own bitcoin node and that node collates its block purely for its asic. LOCALLY then that is solo
ck POOL is a pool. CK manages what work the connected asics do. not the asic owner.
the block collation and simple hash to work on is not created locally at the asic user level. its created at the pool level, by the pool owner.