Are you using net_graph 5? Freezes should show up there unless your entire PC hangs. Please show a screenshot of net_graph 5 during one of these freezes.
How often do the freezes happen?
The past 48h you've only played on the Dutch KroketBrigade servers, could you try other serveme.tf locations? I've sent you a serveme.tf premium code so you'll have an easier time finding servers in all EU regions.
I've run a trace to your IP from the KroketBrigade servers and it's showing packet loss in the last two hops (close to you), in a Virgin Media router. This would point to congestion or connection issues on your ISPs end. A trace from another serveme.tf EU server shows no packet loss, as it's routed through a different Virgin Media router. I would expect no issues if you play on this server (WilhelmBrigade).