External Hard Drive Won't Open On MacBook (already ExFat)

I'm trying to access a 5TB external hard drive (Seagate Portable Drive) on my MacBook Pro and can't open it. The drive doesn't show up in finder and can only be seen on Disk Utility, where it says the external drive isn't mounted. When I try to mount it, it says it isn't possible. I've run first aid on the hard drive and nothing came up. The hard drive is ExFat so it should be compatible with Mac? I don't believe the hard drive has any storage space left (laptop has 25GB free), so maybe the hard drive doesn't have enough space to left to actually operate? I'm looking up solutions on Google but am concerned about corrupting/accidentally formatting the entire hard drive and loosing the material (which I need for a job). Would really appreciate any help or recommendations, thank you!