I am consider to get a Deco P9 whole home powerline mesh wifi solution to replace existing system. I would like to check if it can actually impove it?

Home broadband speed is 80Mbps with Sky Q. it can just about to reach my outer building which is 25m away (33m from the router to the outerbuilding with just 1-2Mbps. I have a devolo dLAN500 powerline and it can reach to the outer building with a speed of about 12Mbps.

I have also tried to put an access point on the 2nd floor windows looking toward the outerbuilding with 5Ghz can get betwen 3Mbps-20Mbps.

all seem quite unstable. with Deco P9 will I get an improvement of these speed both powerline and wifi?

I am also thinking potential of putting one of the Deco P9 in a shed which is about 10m:15m between the house and outerbuilding, if that help?