ようでは

If something is like this, then (a bad result follows). The speaker judges a present state or behavior and warns or criticizes that, at this level, a desired outcome cannot be achieved.

Used in both speech and writing to warn, scold, or give advice, often from someone evaluating another's attitude or ability, such as a parent, teacher, or boss. The second clause is typically negative, like できない, 務まらない, or だめだ. Compared with plain ては, it carries a stronger nuance of the speaker's judgment that the situation is at an unacceptable level.

• てはN2「ては」attaches to the て-form and has a conditional meaning close to「ようでは」, focusing on a negative prediction about an action or situation;「ようでは」attaches to the plain form and adds an evaluation that the preceding state or degree is undesirable.「ては」also has a usage expressing repeated actions.
• ていてはN2「ていては」attaches only to the て-form of verbs and stresses that problems will arise if an action or state keeps continuing;「ようでは」can also attach to adjectives and nouns, focusing on an unfavorable evaluation of the preceding state or degree. When the preceding item is an ongoing action, the two are often interchangeable.
• たら最後 / たが最後N1「たら最後」attaches only to the た-form of verbs and stresses that once you do something, it can never be undone, with the following clause usually being a conjecture or assertion;「ようでは」attaches to various word classes and centers on evaluating the preceding state or degree as undesirable. They are generally not interchangeable.
• が最後N1「が最後」stresses that once you do something, you fall into a state from which there is no turning back; it attaches only to the た-form of verbs and leans toward written style, while「ようでは」makes an unfavorable evaluation of the preceding state or degree and draws a negative conclusion, with broad attachment and a neutral register. They are not interchangeable.
• としたら / とすればN3「としたら / とすれば」is a neutral supposition where the preceding item is uncertain or contrary to fact, and the following clause is usually a conjecture, question, or judgment;「ようでは」carries an unfavorable evaluation of the preceding item, which can also be the current situation, and the following clause is mostly negative. They are generally not interchangeable.

ては and ていては also link a condition to a bad result, but ようでは adds the speaker's critical judgment that the current state is at an unacceptable level. たら最後/たが最後 and が最後 describe an irreversible consequence once something happens, and としたら/とすれば are neutral hypotheticals that do not imply criticism.