I don’t understand why you have such a high cleaning fee if you do short stays where it would be prohibitive and this lose interest by guests you clearly want as you are seeking to waive the fee for them.
Easy solution. Lower your cleaning fee to an amount you are happy to charge EVERYONE and adjust your rate slightly higher to make up for lost revenue. You’ll actually make more from guests booking over x nights and it would be worth you doing some statistical analysis to work this out if you are so inclined. Eg look at the no of bookings you had in last 12 months x $100. Then work it out x $25 (new cleaning fee). Divide the difference by how many nights you had booked last year and increase your rate by this amount per day. Given costs go up each year, I would increase it by 5% so you stay on top of CPI.