> - Tailscale with Mullvad exit nodes
Tailscale is completely unnecessary here, unless OP can't connect to Mullvad.net in the first place to sign up. But if the Indonesian government blocks Mullvad nodes, they'll be out of luck either way.
> - Your own VPSs with Wireguard/Tailscale
Keep in mind that from the POV of any websites you visit, you will be easily identifiable due to your static IP.
My suggestion would be to rent a VPS outside Indonesia, set up Mullvad or Tor on the VPS and route all traffic through that VPS (and thereby through Mullvad/Tor). The fastest way to set up the latter across devices is probably to use the VPS as Tailscale exit node.
Tailscale + Mullvad does have a privacy advantage over either one by itself: the party that could potentially spy on the VPN traffic (Mullvad) doesn’t know whose traffic it is beyond that it’s a Tailscale customer. Any government who wanted to trace specific traffic back to OP would need to get the cooperation of both Mullvad and Tailscale, which is a lot less likely than even the quite unlikely event of getting Mullvad to cooperate.
True, but OP's threat model doesn't involve state actors outside Indonesia, so traffic analysis of the "last mile" between Mullvad node and whatever non-Indonesian service OP is trying to use (Twitter, Discord, …) is not really relevant here. (Assuming Indonesia doesn't have capabilities we don't know of.)
What might be more interesting is the case where the Indonesian government forces Twitter/Discord to give up IP addresses (which I find hard to believe but it's certainly not impossible). But then they'd still have to overcome Mullvad. It's much more likely that if OP has an account on Twitter/Discord, it is already tied to their person in many ways, and this would probably be the main risk here.