Thanks for your question. I think these links will help you find some inspiration and give you quite a few suggestions of what might help:
All of them are worth reading and pulling ideas from. At a basic level for summer, I’d wear a button-down collared dress shirt, some creased lightweight chinos or lightweight wool trousers, a nice belt, a pair of nice shoes (ranging from suede bucks with chinos to leather-soled wingtips with wool trousers), and an unconstructed cotton-linen blended jacket that you can either take off or leave on. Just make sure your shirt and trousers fit well so they don’t look baggy. Maybe keep a solid silk knit tie in the office in case you have a meeting.
On the note of ties being “corporate”, I’d kind of disagree. I think there are casual neckties. Silk knits are definitely in that category, but it’s really more or less in the context of how it plays with the rest of your clothing.
Hope this helps!