I think Chelsea should sign a better goalkeeper rather than signing a striker now. I don't like Robert Sanchez now. He isn't a player who is at Chelsea's level at the moment. Kepa is also not coming back at least until the end of the season and I doubt his future at Chelsea later as well.
There have been rumors circulating that Chelsea are monitoring Arsenal goalkeeper Aaron Ramsdale, but it seems that this is just a rumor, although often a player's move starts with a previous rumor, finally confirmation is obtained by seeing the player sign a contract with the rumored club. Robert Sánchez at Chelsea was indeed a mistake and maybe next season or in the nearest transfer window Chelsea will try to correct this mistake by buying a more reliable goalkeeper with minimal blunders.
Yeah Ramsdale is unsettled at Arsenal right now but that doesn't means Chelsea will sign him. Chelsea already had recently signed Robert Sanchez and signing another good and experienced player will add another player at bench. It will be same situation for Ramsdale again. Even if there is rumour, I don't think it will materialize in the end. I feel Sanchez is a very strong keeper and doing a great job. It is their defence which is letting them down.