In यो घर त्यो घरभन्दा ठूलो छ (this house is bigger than that house), यो घर (this house) is the target and त्यो घरभन्दा (than that house) the standard. भन्दा with ठूलो already forms the comparison; an extra word corresponding to more is not always required.
2. अझ versus धेरै
अझ राम्रो (better; still better) means better/still better; धेरै राम्रो (very good) very good. धेरै ठूलो (very big) alone need not compare two items explicitly; use a standard such as Bभन्दा when required.
3. Superlative and comparison set
सबैभन्दा ठूलो (the biggest) is biggest; यीमध्ये selects the set among these. In यीमध्ये यो सबैभन्दा ठूलो छ (this is the biggest of these), मध्ये establishes the group and सबैभन्दा the superlative.
4. जस्तो versus जस्तै
तपाईंजस्तो साथी (a friend like you) is a friend like you. जस्तो also has जस्ती/जस्ता forms. तपाईं जस्तै (just like you) expresses similarity such as just like you. Compare complete noun/adverbial constructions, not isolated translations.
5. Equality versus difference
A र B बराबर छन् (A and B are equal) states equality; Bजति compares an amount/degree to B; Bभन्दा introduces a standard for difference. The marker distinguishes equality/degree from unequal comparison.