Nowadays Windows is filled with adware and is fairly slow, but it wasn’t always like this. Was there a particular time where a change occurred?
Windows Defender is actually really good for the common person. If you’re doing highly risky things then perhaps getting better software would be warranted. But if your doing low risk activates, Windows defender is pretty great.
Also, that’s not what VPNs do; you can still download ransomware through a VPN tunnel.