How much should I pay attention to the Bid-ask spread and Open interest when buying Deep ITM options?

I plan on buying Deep ITM options for ex.

SPLG $42 call expiring on 12/19/2025z

The bid is $26.70 and ask is $31.50

I read Heather Cullen ITM options books and wanted to try out the Strategy outlined in those books, but the wide bid-ask price and low open interest has me skeptical does anyone have any advice on what I should do or how much these things matter.

I plan on holding the contract until about 30 DTE.

I want to buy the contract, but the low interest and wide spread has me worried.