Fee Rate as decimal number - how to define e.g. 1.5 sat/vB?

Dear all,
recently the bitcoin fee rates are quite high again and transactions with 1 sat/vB are stuck for days of even weeks.
Looking more in detail to blocks containing transactions from e.g. 1 to 137 sat/vB, are showing lowest transaction fee of 1.x sat/vB, e.g. 1.54 sat/vB.
In my wallet, i can only define fees in integer numbers like 1 or 2 sat/vB.

My question, how can I set a fee rate of 1.5 sat/vB?
I am looking especially for solutions like “Ride the Lightning” of for lncli?