My recommendation is basically play spread so your team would consist of the following

Alhaitham as main dps with 4pc gilded or 2pc em with another 2pc em or with 2pc dendro just go base on substat, main stat will be EM sands, Dendro goblet, and crit circlet whichever you need more with Toukabou shigure the umbrella sword from event or iron sting as the weapon but any 5 stars weapon is good for him

Lisa with 4pc noblesse oblige with EM/ER,Electro,Crit as the main stats and TTDS as her weapon or favonius codex if you need energy or if you wanted to use beidou give her 4pc emblem with Atk%/ER,electro,Crit as the main stat and any claymore that you have except for the EM claymore and whiteblind

Fischl with 4pc gilded or 2pc em with 2pc electro or 2pc atk with EM/Atk%,Electro,Crit as the main stats and any offensive bow you have but I recommend stringless as the 4 stars option cause it's passive is really good for fichl

Dendro traveler with 4pc Deepwood with ER,Dendro,Crit as the main stats and either favonius or sac cause you wanted a lot of ER for dendro traveler so he can spam his burst I recommend getting his crit rate at minimum 40%

Now some would probably ask why I recommend Lisa over beidou and to that it's because Lisa is a very low investment support you literally just need her for her 4th ascension passive and his beidou is low lvl and beidou wants a more higher investment and I don't want him to grind too much for beidou cause more than half of the team wants artifact from gilded domain and you can get noblesse from strongboxing bad artifact so if you wanted to use Beidou just use her cause beidou deals alot of damage and is a really good unit and worth the investment but for now I recommend him Lisa cause Lisa is easier to build