[Xiaomi Mi A2 ROMs, Kernels, Recoveries, & Other De] :
Nope, You don't need to root ur mobile.

The developer has already enabled the API (CAM2API) required to run the GCAM module.

You just need to download and install one from the link provided in this post (Don't worry, It's a trusted GCAM modules site) and u r good to go.

Screenshots of working Gcam below:

[IMG="Camera Ui"]https://lh3.googleusercontent.com/R_vdSaNIQ2x2nSNk8SR2xCRPgYRKMbd_1rzxuWGofDh-Svho4dCirNtb7ba91jeqoP4oSwfk5bloSECgpHelSZXgqZaaQ_f4rMGv_zffTgzndEFFb5F08qurl1UiwP2R3J1QmA21B48I5iVEDxxskcJ_Vy5OF7-X8ZNM5lKdD7lSjR9fYEaFME0w0yh8ZOcBcdafoFxZhHDE_5vCXZQkaD6sS-uTo5ID0xunMNKwy6bS4kNvCAEOjRgqTxGHYHqkjxKxEiSXNuZ-CReCZxiBtkqpgRqxKQW_cZECEKtIS0FREGzfD1V7UavxpgX0vDHfT2CPt36xHxr857D8F_KGqmb3M4fTQQenJVoDzm-08nV51IOyIATLRu04TiJVx8AvXEXxAMq2_gBdHD5ssTkljok_z5HuyvKyO3tNyp-yicr1n3jEThCbPM_Hq9JzVwZTQle_P0YRvnlhxUWgcV3ZIY90uYQYbt0mWu-VsD6oRvm6jBLnEa1stvauuTBww0QcrXDGv0NT_HZ7WKEUw8rpaO_KIVQpKBeCns6Dqb5qiryYJIzUO-SRwIBodnTueFBVyn714z5QaTUIubYWaggZt01O39CxXZck0lvy1CUNzu5cGhGfcZOq1tBSVuB6y1CTe-W1U2cwZUUpMBC4tqqsGVx148wDPUzD9F_LeIEiFlJR8706plQ_Wqg=w447-h893-no[/IMG]

Camera UI

[IMG="Potrait Mode"]https://lh3.googleusercontent.com/YDGvsbyAUFts7Vmft_E3hUwNZvh7ZsXo168D5Cdq1wLGPngZRuMZXYKWD5YfIFfNpMwrGWTgfPlMy3lCdEB3hq5AMNr4Gbc7xFzqP1D_GGVD5l8x6_DFPpjSlekMdheG9Whqo4Z-IiJkB8qiq67jEMdrxNeZSVUBntohHY5Sn0yt0ID8NfbDeB1XoJIcnEd31xcsg2BLI-na0H7g0kCr62Sqzb3F7P3KW4xVzEm-Esc3SVPcXLHrTCF25O8Pu1n0cvmdSseUzfbthwkD-0m8J5-brGODChXb-CpEtLJKaySVJl_n3G7PItRTq_bH12xDzQd2K4XEzlvUBltR4pUH1IswtEqiKv1hMY9R21UcDezlhkKpgi7_7RVsFYiubgOWeDy29prDj0Q0DUyomOUqfQiyBAKvthGlYuOvJKwOfCVJA0IgFyoRQ0wxla44PqfKD_06AiIx-Ob4rAniy4l3h8Tzildri6ETBUpJ2y5ySwB7Qcq5lsv-Nk6t5Iaq7DXULCt2PYML3xeyqpevDx_KaiOzLWuNIibSaITatJfnpNRGblUyPkvN9qkz4o_yVxKuoilbmwEE50VLuct45uJAYBxN1pqcTZhm_IDia3997hA5n9UcPDgISfgLMV5NMMwjQHczliVJ9Ej7Wi0gQHHW6ivr7eNakVXBSMKkbrA51SPfRhxxIBRqUFQ=w670-h893-no[/IMG]

Potrait Mode

[IMG="without Night Mode"]https://lh3.googleusercontent.com/mJQBGoYsjxZFGQG4f3_R7auQjIYIEndj33FjQMq4mcdD7oFvWgwPyBLQ4hrGs8BTrRuCNOlFGh4zCABVMuzsO65HMOYQPn5pRZa6_bnSsQLw6M4Qt3nAguMTCVPEVCz3aYjo19EQ6o3KJLusOd-H0Fz0pPMdfn2dYDEqrwnrIQs9ZFYXWFdN3VUt0VtTqe1pDj6Hj9rx9rGQzitBXzYXz9Tdvx4-Sf_FmOacwdkWFK40ltRpvv7XGP5AOcSKndlXT2fgw7yX4EYnxnehi_JnspktZ9eL09N2bCm5XxQYZ2qu2-hRBtupxD5JLXCoLmY_ZLOkIhEnrU9HrwJ1mwymWWbuVuI0joJtZWnyQTCYRLuTY7nnnQfNw3ZSZf3zHm9gpGMTgf3N-OMin5jCZmmrj84e7-KL3UUtPKOvBdhsvnb0nZt_5USNuFedQH1-OUTVu7zv8Ay_luNmNlXZ9TS8mIp8qsw8OtIXpaSCjCIa4jaiw--hq0zUKb5PMthQvcvbhNM61d1NotE_Igu5ro9rTwCvEJgAN3ohu2Oa9wozkOfyndFtU_DdSQY60mbjk8m7W7Pb76OalJYq6pHMau91Jx1NxhAN16rDEVItGAdjTFw6XTruPXQEI6TBG3KziKkT0M5n5OYGNP1cPkEsrMvQgG6e0msa4wrATp0rDv3OBSsR3bhp6rQ5Ygg=w717-h954-no[/IMG]

without Night Mode

[IMG="with Night Mode"]https://lh3.googleusercontent.com/mjMM0ePBhZgMQzrD_EPHTqUnkKdbDKRBz_JtltTnmWB3qAlYnOugqlggBYRFVKYt-d9sAdz7PS02iQB3iF87mF2ZoU6AM7CEjLbNgJ4cUbIT6IolvVlVuSoFgwd0aj3Ue2FdATXgGPPZEA_nqAn9xQCER2G0NCPYSa9X4lIYmO8AhtelcmWvD_fKbia5qv8PL1plMUF2sFZqtQiN2c26Svq5SbJZzrKi4jOUx_1wryt_pfnOFNPtz46QBgBGf8gp_PB_mssJbUHOCcrElvSkUoll53_0TW_jafTjD6PS-dqfYC89GSTYuODva8-VF3MlHiD8fdLQCoancp171b4I-HXieM0z_hW7pBkIkOhDod9L1jFccveUVLmV3P0OeyLDFvKHBMZYtKvcKDtckXD0mSy1TDivdHsN5joFei7NxhBYEqeH0NL3eCz1Fq9zLR8Idh491YcF_Am2ivRVxtsaB9W0ApZxtc7SKdaRSP8jSRL1IfZQID8T9jUbUVbmgWzKM0OuhzalhxLldXgCJcsU7DRAF9Jm_6-03nc72iA7f8Shy4DC4gymrgWCzKGo83ijJf1Rq6TeGXV4cmk28i9caBj558ylR9yBMlo09_eT78Oy3WCejPegBLUWZzenXHWI2RZ0qQuy3ooH66uihVfHXrS5SzdwNH5Xtugfam-dqTtCeDRn_0L8GJA=w717-h954-no[/IMG]

with Night Mode

Sorry, I don't know how to attach screenshot (images) separately under the post. If anybody does, Please let me know.

Thank you.