Is the word comi the same in Brazilian and European Portuguese?

Yes

The word "comi" is identical in spelling, grammar, and core meaning in both Brazilian and Continental Portuguese. The only difference is in pronunciation. In Brazilian Portuguese, the "o" is typically pronounced with a more open vowel sound ([kɔmi]), whereas in Continental Portuguese, the "o" is more closed or reduced ([kumi]).

Brazilian Portuguese Examples

1. Eu comi um sanduíche agora há pouco. (I ate a sandwich a little while ago.)
2. Comi demais no almoço de hoje. (I ate too much at today's lunch.)
3. Comi a pizza toda sozinho. (I ate the whole pizza alone.)
4. Comi uma fruta para ver se passava a fome. (I ate a fruit to see if my hunger would go away.)
5. Ontem eu comally comi um doce muito gostoso. (Yesterday I ate a very delicious sweet.)

Continental Portuguese Examples

1. Eu comi um sanduíche agora mesmo. (I ate a sandwich just now.)
2. Comi demasiado no almoço de hoje. (I ate too much at today's lunch.)
3. Comi a pizza toda sozinho. (I ate the whole pizza alone.)
4. Comi uma peça de fruta para ver se a fome passava. (I ate a piece of fruit to see if the hunger would pass.)
5. Ontem eu comi um rebuçado muito bom. (Yesterday I ate a very good sweet/candy.)