Problem whit Queues

hello good morning everyone, I am facing a problem with “queues” my mikrotik server. today i have a x86 pc Ryzen 7 2700 8/16 running native mikrotik v6.47.1. I happen to be having a hard time keeping bandwidth stable for 100mb plans. in fact I put it up a little bigger to see if it could make a difference and nothing. I set up 110mb for download and initially, using the speedtest.net application, I can beat the 109 … for a few seconds but after a few seconds of testing the band gets to drop more than 40% and soon after it starts to gradually rise to close to 100 but the test ends before that. if you remove the bandwidth control, all my speed passes without any problem, which is 300mb. I’m using an android phone, AC router and pppoe connection to this serviver and speedtest application as a laboratory for this. could someone give me any suggestions?