Vraska relic seeker and karn together will build a strong board pressence -2 and -3 as much as possible to give your enemy alot to deal with time is on your side the deck will generate huge resource with cabal stronghold's chromatic lanterns and gilded lotus. As far as the treasures go it is best to save them for cast banefire or hydroid krasis or even vraska, with using treasures to make vraska its not so bad because even if you can only keep on board 2 turns you generate a profit in resource. 

we keep a chromatic lantern in sideboard incase the one in main deck gets unmoored ego'd even if the lantern gets exiled or ixialan binded you can still function on the lotus. Lotus is a great card on turn 5 you can cast it and 3 cost 2 spells on turn 5 is very good value. 

we can deal with most threats using mastermind aquisistion for example on we can respond to t6 niv mizzet and lyra dawnbringers by doing a masterminds into side board for price of fame which is a good value card surviel 2 and only cost 2 on legendarys. having an answer to big legendary threats and improving the next 2 draws is strong. 

This deck is consistantly getting 4 to 5 wins on bo3 constructed events on arena.

Personal opinion i rate this deck

2/5 Speed - Does not really generate any threats till turn 5-7

5/5 power - Being able to overpower the strongest creatures out there with karn tokens and cannot be outmatched on hydroid krasis size potiential.

4/5 control - Strong early game clears in cry for the carnaruim, cast downs, moments of craving. Late game clears and cards the can deal with any threat that can be tutored with masterminds aqqsistion.Generates an overwhelming amount of mana and uncounterable card draw with hydroid krasis. Finishes with a counterable bane fire oftern. Hard removal and resource gain in a planeswalker(vraska relic seeker) No counter Spell magic stops it getting the 5

5/5 syngry - Karn makes tokens we drop artifacts to make them stronger and vraska makes artifacts while killing there creatures. The artifacts generate mana to make Hydroid krasis bigger. 

4/5 Overall - Solid balance , Layered threats and Good Syngrys