Slow dns/no dns after cold computer boot

I sometimes have to wait 1-5 minutes before webpages load(or are recognized by the browser for that matter) after a cold boot(pc). When this happens i get either one of the following errors dns_probe_started dns_probe_finished err_name_not_resolved. the webpages load after a while but it gets annoying because it happens rather often. this happens to all 4 computers in my home although it's mostly happens on the 2 fastest computers with ssd's (my guess is because they boot extremely fast).

I have an cisco epc 3925 wich functions both a modem and router. the epc 3925 is hooked up to a DLink gigabit switch which connects all computers in my home. 3 computers are running windows 10 and 1 is running windows 7. all computers have been scanned with malwarebytes and get clean results. My Isp has had dns issues in the past which made me set the dns in my modem manually to the google one (8.8.8.8) (8.8.4.4) which fixed the issue then but does not now.

Things i've tried: reset modem (multiple times) tried original dns settings (and automatic dns settings on the pc's) configured all computers and my modem with the google dns ipconfig /flushdns

netsh, winsock reset (which seems to fix it for the first next boot)

I don't know whats left to try, besides this doesn't happen all the time. sometimes the webpages load instantly like usual after a cold boot. this makes it even harder to pinpoint the cause. Any suggestions? Thank you