Hi @moonman !
Here are my two suggestions & I’ll throw in a wildcard third…
First, get a sleeved trisuit. I had good luck with the 2XU sleeved tri-suit. Their aero version. This tested really well for me, which can be an individual thing…but I feel reasonably confident in saying that any decent sleeved suit will be faster than what you are wearing.
Second, get a disc cover for your rear wheel. I like EZgains product but have also used wheelbuilder’s disc wheel cover.
Wild Card…Rudy Wing is a pretty fast helmet on most heads. I’ve taken a lot of aero data on tri helmet options and the fastest on my noggin was also the cheapest. You can read about it in my thread…scroll down to see the helmet. Don’t know if it’s still available. But there is a cheap option you can get & test just to see.