why is this slow as hell?
It's generally a function of CPU/storage device/network... Note that your computer isn't just "downloading" 350 gigs... it has to process and validate all the transactions/blocks that it receives as well. This is disk/CPU heavy. If your hardware is not great (ie. HDD instead of SSD, older CPUs etc, low RAM), that will slow things down.
looking for ways to bypass the sync process for bitcoin core.
The only way to do this is to get a copy of the blockchain data from a fully synced node from a
trusted source.
If you really don't want to wait and don't need to be running a full node, then switch to a lightweight "SPV" wallet like Electrum or Wasabi.