Interest income was .86 for 2020, I didn't get a 1099-INT. How do I enter this information?

Ignore it.
IRS received no info because the amount is too small, and $0.86 won't affect your tax liability.

The IRS requires you to enter all income: “Your worldwide income is subject to U.S. income tax, regardless of where you reside.”

Eighty-six cents ($0.86) would be rounded up to $1. When rounding off numbers, drop amounts under 50 cents and increase amounts from 50 to 99 cents to the next dollar. For example, $1.39 becomes $1 and $2.50 becomes $3.

You don’t need a 1099-INT to enter interest income. Enter the name of your bank and the amount.

• Type interest in Search in the upper right
• Click Jump to interest
• Select Add another 1099-INT
• Hit Continue on Get ready to be impressed
• On Let's import your tax info click Change how I enter my form
• On How do you want to add your 1099‑INT? select Type it in myself
• Enter the name of your bank and fill in the amounts that match the boxes on your Form 1099-INT

I received a 1099-R from my last municipal job and a W-2 for 0.05 in wages (no letter of explanation).
No $0.05 deposit to the account where my salary and now my retirement goes.
I ignored it. We'll see what happens.

The IRS will ignore a W-2 reporting less than $1 in wages, so you can ignore it as well.

If the interest amount is under $10, you will not receive Form 1099-INT.  Therefore, the interest amount is not reported to the IRS.