English can present a learner with some tricky consonant sequences at times. An example is the sequence ðz, as at the end of the word clothes for example. Resist all temptation to break up the sequence with a vowel, resulting in a pronunciation like ˈkləʊðɪz! If you can’t manage the sequence, just get rid of the ð and say kləʊz. Native speakers do it all the time.
The sequence zð is just as tricky. What native speakers quite often do is turn this into a long z sound. So for example the phrase is that gets produced as ɪz zæt. As long as you don’t pause at the end of the first word, you can get away with this too. But don’t say ɪð ðæt instead.