As to what  you  should buy next.

S17 pro with 3 speeds

s19 pro with 1 speed

I would buy an s17 pro with 3 speeds.

Basically buying s19 pro with 1 speed means you are going to need to use aftermarket firmware.

I have a mix of

s7ln      1 piece
s9       19 pieces
s9i        4
s9k       4
s15       1
s17       1
s17pro 14

t15        1
t17        2
t17e      2
t17+      1

avalon
a721     1
a1041   2
a1066   2

whatsminer
m10     2
m20     2
m21s   1

innosilcon
t2t24    1
t3t39    1
t3t50    1

and  of all that gear above  I need to run 6 units at less then top speed or they overheat and crash.

So to me  I will get:

1 s19 pro
1 s19

work with them  decide if they are okay.   If they have 1 speed they are not okay.

I will look for a low priced s17 pro with 3 speeds.

I do not use any aftermarket firmware on all of the above

except for 1 s9 it has braiins.

having a 3 speed s17 pro or s19 pro if it does that  is my choice going forward.

My 14 s17 pros are all under paypal warranty so I do not fuck with aftermarket firmware.