[3] In February 2020, Miantoro advanced to the finals of the Italian Junior International in girls' doubles events, but the tournament was canceled due to the outbreak of COVID-19 in Italy.

[8] In July, they lost in the first round of the Singapore Open from 5th seed Chinese pair Zhang Shuxian and Zheng Yu.

[11] In March, they lost in the final of Vietnam International from Korean pair Lee Yu-lim and Shin Seung-chan.

[12] In September, they won the Indonesia International tournament in Medan, defeating her juniors pair Velisha Christina and Bernadine Anindya Wardana in straight games.

[13] In the next tournament, they competed at the Indonesia Masters Super 100 I but lost at the quarter-finals from 2nd seed and eventual finalist Chinese Taipei player Chang Ching-hui and Yang Ching-tun in straight games.