LAG on SwOS

https://wiki.mikrotik.com/wiki/SwOS/CSS326#LAG

Each individual port can be configured as Passive LACP, Active LACP or a Static LAG port.

Property	Description
Mode (default: passive)	Specify LACP packet exchange mode or Static LAG mode on ports: Passive: Place port in listening state, use LACP only when it's contrary port uses active LACP mode Active: Prefer to start LACP regardless contrary port mode Static: Set port in a Static LAG mode

Property	Description
Group	Specify a Static LAG group
Trunk (read only)	Represents group number port belongs to.
Partner (read only)	Represents partner mac-address.

 https://forum.mikrotik.com/viewtopic.php?t=126149

Hello, why are you configuring LAG ports as static? and the second one, to configure a LAG with SwOS it's like a LACP so it has some modes where those switches can negotiate the LAG port:

Passive: Place port in listening state, use LACP only when it's countrary port uses active LACP mode
Active: Prefer to start LACP regardless countrary port mode
Static: Place port in LACP mode=on

So if you want to configure a LACP link you need to get this combinations on both sides:
Active - Active
Active - Passive
On - On

https://forum.mikrotik.com/viewtopic.php?t=138066

You can do and should do lacp
This is exactly what you need, 2 links combined for reliability and redundance.
Rstp has nothing to do with this.

Lacp well there is not much to configure, it is missing long and short timeouts but thats it, there is very little configuration. Just make sure that one of sides is in active mode, or set both to active.

Static team or static lag is same as lacp, but you have to define ports, specific ports on which team is made.

For me, lacp and static teaming are not working at all on my server 2016 box with 3 nics...