FYI, fixes have been pushed to the repository, so if you delete
C:\Users\<user>\.platformio\packages\framework-arduinorenesas-uno
And in the platformio.ini set
platform = https://github.com/platformio/platform-renesas-ra.git#a0d14d9b9f53808da8f80095aba368044ef00d94
(or, @1.0.1 I hope, soon).
Then you should have framework version 1.0.2 (fixes the bugs in WiFiUDP/WiFiSSLClient library) that has on top that of my RTC fix included. Then no manual file modifications should be needed.
Can you test whether that then works out-of-the-box?