> Platinum Honors which gives me a few extra percent cash back on credit card purchases.

Customized Cash card? That gives you 5.25% back on the category of your choice up to $2500 spent each quarter (saves $525/yr). Your saving earns 0.04% ($40 for $100k).

Discover is 3.6% right now ($3600 for $100k). Then whatever credit card savings you get.

Even just a 1% saving account will save you about 2x what you get now.