Mikrotik sxt lite2 as a router?

Question

Mikrotik

Hello to all. actual subject. I need help setting up Mikrotik as the first device from the provider. because I live in the private sector, but I want the Internet, I have to pervert.
the scheme is as follows - the provider's router -> lan sxt2 -> over the air connection to the access point ubnt picostation -> lan port ubnt picostation m2 on a computer or on a switch. but for now comp. <- the ubnt bullet m2 endpoint connects over the air to the ubnt picostation point->lan ubnt bullet m2 goes to the rb951 router, from which my devices on the network are already powered.

the question is this. how to configure sxt2 so that it can be accessed over the air without problems? those. sitting at rb951 from any device, I could go to sxt2, but the separation of my network from the provider's network was by lan, and not by wifi, as intended in the cpe script?
now I have access to the network from a friend, but the link is too long. about 4km and heaps of points. the scheme is something like this - the
provider's cable enters the apartment - the router - the ubnt NS m5 (AP) point is sent via cable to the ubnt NS m5 (station) client device - then the whole thing goes through a couple of switches to devices in the house and goes to the ubnt client device NS m2 (station), which in turn is connected to ubnt bullet m2 (AP) and my ubnt bullet m2 (station) is already connected to this bullet, and then rb951 and my devices. the speed at the same time rarely rises above 5 mb. and we have one common network. besides me I have a few more client devices.
immediately the circuit is simplified to 3 segments.
the question is this. how to configure sxt2 so that it can be accessed over the air without problems? those. sitting at rb951 from any device, I could go to sxt2, but the separation of my network from the provider's network was by lan, and not by wifi, as intended in the cpe script? make lan port wan port.
or still leave this idea and swap bullet and sxt? bullet in soho router mode and no problem, but sxt in ptp brige?
Oh yes. The pico station uses a bi-square type antenna, but with a 180-degree sector. to make the signal more or less directional. link distance 800m. the directional antenna on the bullet is large. so I don't really want to put it on the roof of the house. little.
and another question. is it possible to exclude the end device on the lan port?