Over 40, need ovulation advice

Need advice....I am 41 with 5 successful pregnancies, but it's been 6 years since last baby. Trying for one last one but no luck for the past year or so. I get LH surges still but my cycles are very short. I have 25/26 day cycles that include a typical 7 day period. We've tried to BD day before ovulation, day of ovulation and day after ovulation. Usually only one of those per cycle due to busy life.....whats going on? Any advice? Pic of one of my ovulation tests

Ov tests