A Research Study Comparing How Well Different Doses of the Medicine UBT251 Lower Blood Sugar in People With Type 2 Diabetes

Inclusion Criteria:

* Male or female (sex assigned at birth, inclusive of all gender identities).
* Age 18-75 years (both inclusive) at the time of signing the informed consent.
* Diagnosed with type 2 diabetes greater than or equal to (≥) 180 days before screening.
* Stable daily dose(s) ≥ 90 days before screening of the following antidiabetic drug(s) or combination regimen(s) at effective or maximum tolerated dose as judged by the investigator:

metformin with or without sodium-glucose cotransporter-2 (SGLT2) inhibitor.

* HbA1c of 7.0-10.5 percent (%) (53-91 millimoles per mole (mmol/mol)) (both inclusive) as assessed by central laboratory at screening.
* Body mass index between 25.0 kg/m\^2 and 50.0 kg/m\^2 (both inclusive) at screening.

Exclusion Criteria:

* Treatment with any medication (prescription or over-the counter) or alternative remedies for the indication of diabetes or obesity other than stated in the inclusion criteria within 90 days before screening. However, short term insulin treatment for a maximum of 14 consecutive days and prior insulin treatment for gestational diabetes are allowed.
* Uncontrolled and potentially unstable diabetic retinopathy or maculopathy. Verified by an eye examination performed within 90 days before screening or in the period between screening and randomisation. Pharmacological pupil-dilation is a requirement unless using a digital fundus photography camera specified for non-dilated examination.
* Known hypoglycaemic unawareness as indicated by the investigator according to Clarke's questionnaire, question 8.