Question about my Insert to liner connection

[MichaelNevadaCity]

The transition from my insert to the ceramic chimney liner appears to be some custom masonry into a sloped iron section then into the 10” ceramic chimney liner.

I am wondering:
a) am I correct that (if I did decide to do the install) that adding a damper is not advisable because I have that irregular flue situation

b) is there a safety issue with this current set up (the masonry and steel all seem beefy and well done but it’s hard to tell about every bit from phone videos with body in fire box and arm up through the flue)

c) it appears that consistent pipe from stove to ceramic liner is not possible due to offset.. which is why they musta done this setup...
is there any alteration that would increase efficiency?

 

[coaly]

A stainless steel liner needs to be directly connected to Insert, and the same size as stove outlet all the way to the top. Preferably insulated. The Insert should have a factory damper controlled by lever or chain on the right side extending through fireplace faceplate. The direct connection of liner extending to the top has been a safety requirement for many years since when allowing hot flue gasses to expand into a larger area, they cool too much forming creosote.