First take a look at the 2020 NEET Cut off data (for the state of Karnataka, to get admission in a Govt college of Karnataka) -

Via 15% All India Quota -

• GN - 615
• OBC - 616
• SC - 508
• ST  - 495
• EWS - 617

Via 85% State Quota -

• 1G - 529
• 1H - 495
• 1K - 501
• 1R  - 510
• 2AG - 521
• 2BG - 520
• 3AG  - 540
• 3BG  - 538
• GM  - 540
• SCG - 431
• STG  - 488

From the above data, it is obvious that with 400 marks in NEET UG it is difficult to get an MBBS seat (in Govt) in Karnataka (via OBC Category). Also, cut off varies from year to year as it depends on number of candidates (who appeared for the exam), difficulty level of question paper, number of newly opened colleges, etc. However to be on a safe you need to target for a score of 630+ to get a seat via 15% AIQ or for a score of 530+ to get a seat via 85% State Quota.

However there are some private (deemed) colleges where you may get a seat, but in that case the fees will be extremely high.

To get more details regarding Karnataka NEET cut offs, you may visit the link - NEET 2021 Cutoff Karnataka (2020, 2019, 2018, 2017): College-wise & Category-wise (careers360.com)

Also, if you want to prepare for NEET UG 2022 online at affordable rates with quality features (like AI Learning, Personalized Timetables, Mock Tests, 24x7 Doubt Support, etc) , you may check out this link - https://learn.careers360.com/medical/neet-preparation-material/