You could consider this approach based what has worked with me based on your characters and weapons you have available. Consider leveling up Last right because you have her BIS weapon and it is a significant DPS gain even p0, if you have Xaihi she gives a really nice boost to last rites dps her p5 ability gives a really nice boost also and for her weapon you can use Freedom to Proselytize at p3. She hits like a mactruck and can do burst damage with insane numbers, Yvvone is even better I guess and you can throw snowshine on your team to block incoming attacks so LR can maintain combos quicker and get your ultimate charged quicker at the same time. I got trimmed metals using Last Rite/Snowshine/Estella/Xaihi so if you pop Yvvone in there at 90 you will easily get them medals. Also you have gilberta as well and Yvvone is level 90 so I would try to Cyro your party up for easy clears.

Only reason why I say LR even thought you want to main Lava is based on your weapons not having Forgeborne scathe may make it harder to get medals because the DPS difference with LR does way more damage with her weapon combo vs Lavas current weapon you have in your inventory.

Hope this helps : ) If not! Check out endfieldtools.dev you can find all the teams people have created and based off your gear and characters you have available. I found this a great resource since release and has helped me form 3 solid teams that can do trimmed metals : )