Not all workplace romances are created equal in terms of spice level. If you're looking for slow-burn with a high emotional payoff but closed-door or low-heat scenes, authors like Beth O'Leary ('The Flatshare'), Katherine Center ('The Bodyguard'), or most of Sophie Kinsella's older books are your go-to. The focus is on the emotional and situational buildup.
If you want the steam factor turned up, authors like Tessa Bailey (check out 'It Happened One Summer'—not strictly workplace but the heroine works at a bar), Kate Canterbary (the 'Walsh Family' series is all about siblings in architecture/construction), or J.T. Geissinger (often features powerful, morally grey bosses) will deliver. It's all about what balance of plot, tension, and explicit content you're in the mood for.