I came across a very interesting short sutta on FB: https://www.accesstoinsight.org/tipitaka/sn/sn20/sn20.005.than.html
Kind of confirms my findings in the last few month. If you make Metta as your default practice, it forms as a strong foundation for Vipassana and Shamtha. Makes practice much less painful and even fun overall.

Thanks for the share, this is a wonderful little sutta
Yes metta is a brilliant practice,
as are all the Brahma Viharas