Spring nights are chilly, so take advantage of the inexpensive price of an AmazonBasics Commercial Patio heater. The heater can output 46,000 BTUs, a sturdy base, and a simple piezo ignition system.
At the end of the day, all you want a patio heater to do is work, and the AmazonBasics version does nicely. You can upgrade to a version with a cover if you’re going to be storing it out into the elements.