I've got no dog in this hunt, but just based on all the reported failures with not only Stage III or IV M8's but also stock M8's, 2017 and 2018 models, I think it might be best to wait until Harley actually fixes the root cause of the sumping issue. The 110 isn't exactly the epitome of high quality, but as long as you do some preventative parts replacements (like lifters every 10k - 15k miles) the odds are decent that your engine won't turn into a boat anchor. On the other hand, the M8's with serious sumping problems are usually trashed and have to be replaced or totally rebuilt. If you have any illegal mods on the bike that repair will come directly from your pocket.
Considering how many years it normally takes H-D to fix their design issues, you may be waiting for an M8 for a few more years.
JMHO - Jerry