Yamaha YZ suspension reply to 450 rider who weighs 220 pounds and is on the stock springs.....
It is very crucial for your bike's overall handling to have proper spring rates and sag. A range of settings is normal, but if you can't get the rear sag anywhere around 100 to 106mm then it's time to consider different springs. I presume you're riding too far into the progression of the travel which is leading to wallowing, understeering, excessive bottoming and riding more rude on the small bumps, too.
Add a backpack or tool pack, buy heavier boots, etc., all compounds the spring rate issue.
Cranking the spring down will decrease some of the bottoming or wallowing but it is a band-aid remedy; it also will take away race sag and static sag. Not enough static sag and the bike will not settle properly and have a "frantic icy" feel at speed.