I saw some new Lithium batteries on Amazon, rated 6kAh (my other ones are 1.2 and 4).  These are about $50 for a pair (so get a pair!), roughly half the price of the 4's from Ryo.  I cannot speak to longevity, but after several uses, they sure do extend the use time.  I was tiring out before the juice ran out, but then I'm more derated every day!  I've only looked for the Ryo ONe+ thing, but I assume other compatibilities are available or coming soon.

 

https://smile.amazon.com/gp/product/B08LPP48M1/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

Thanks for the heads up!