Why is OP_SUBSTR disabled? (and OP_LEFT, OP_RIGHT)

Why are the substring opcodes disabled?
I understand that OP_CAT is disabled because it can blow up the stack easily (in combination with OP_DUP).
But the substring opcodes reduce the stack size.

Context:

I’d like to use OP_LEFT to implement a proof of work requirement to
spend a transaction. A substring operation is needed because OP_ADD
(for salting) and OP_GREATERTHAN only work on 32bit values.

Multibit HD only sees one peer

Multibit HD is only connecting with one peer. This issue randomly started a few weeks ago. Initially, I had to keep restoring my wallet to a previous date since my balance kept reverting to uncomfirmed. Annoying but it was a work around, until it only started connecting with one peer. Restoring the wallet does not resolve this issue.

Bitcoin Core works just fine. Ports 8330 and 8333 are open. The issue happens both on, and off, a vpn.

Any thoughts on how to troubleshoot this issue, or at least get my coins out?

Thanks!