Config.json options to speed up relay node sync

What options could I tune from the config.json to speed up the synchronization of an archival node for mainnet.

From the default config.json when using algod 3.5.1.stable [rel/stable] (commit #aa2fb0ee), I have modified this:

AnnounceParticipationKey: false
DNSBootstrapID: mainnet.algorand.network
DNSSecurityFlags:  0
CatchupParallelBlocks: 32

are there any more parameters that can be adjusted to speed up the process or any parameters to run concurrent/multiple processes to get the node sync faster?

Config tweak wouldn’t help much. The best way is to use a “local NVMe” storage. I was able to get my node to full sync status in about 15 days.

What is the required current space, raid 0 help?

2 TB is recommended; be prepared for a bigger storage as Algorand grows. I wouldn’t bother to set up raid 0.

I would strongly recommend against this, as it potentially reduces security: not using DNSSec.
The only case where you want to use this is if your ISP is blocking DNSSec (which unfortunately happens sometimes).