With only 5W of output power, it shouldn't be a super bad issue, but still something to take into consideration. I was building a 300W Boost converter where ESR was a HUGE deal due to output ripple current and power dissipation. (I blew up more than a few capacitors haha).
I dont believe ESR will effect the output voltage much (may cause a little ripple), but it could effect the current more.
These tutorials were a great help to me:
https://www.powerelectronicsnews.com/technology/the-dc-dc-boost-converter-power-supply-design-tutorial-section-5-1some of stuff went over my head but some really did help me. Maybe it can help you out too.
What I would do I calculate the ESR of your cap, then throw it in a SPICE simulator, and model it with the calculated ESR and other values. I can help you if you have LTSPICE or TINA-TI or PSPICE. See what happens at the output.
To calculate ESR, you have to look at the datasheet of your cap. If it is electrolytic/aluminum, it might have the ESR listed, if not, look for the "tan(δ)" parameter. This is called the dissipation factor or DF. Then calculate ESR from this link:
https://www.illinoiscapacitor.com/pdf/Papers/impendance_dissipation_factor_ESR.pdflet me know what happens. you can send a message if needed cuz i dont check the beginner forum a whole lot