MitM: As some apps use certification verification, MitM will not work.
ShadowsocksR: The protocol development had stoped.
Surfboard developer intend to follow protocols Surge supported, other protocols such as V2ray/SSRR/Brook may not be supported.
disable your "always on VPN",then you can trigger Surfbord VPN access.
If you are on old Android versions (6.0 or older), there will be a toggle to disable monitor on setting tab(if you are using Flyme, just give up, don't ask why).
If you are on stock 7.0 or above, you need to use a system-wide feature calld "Power notification controls" (if you are using Samsung's 7.0-based Android Phone,go Oreo or just give up this method).
Otherwise, you can just disable Surfboard's notification.