BUG: DatetimeIndex and Timestamp behave inconsistently with respect to pd.DateOffset
### 

- [X] I have checked that this issue has not already been reported.

- [X] I have confirmed this bug exists on the [latest version](https://pandas.pydata.org/docs/whatsnew/index.html) of pandas.

- [ ] I have confirmed this bug exists on the master branch of pandas.


### Reproducible Example

```python
pd.DatetimeIndex([pd.to_datetime('2020-10-25').tz_localize('Europe/Berlin')]) + pd.DateOffset(hours=3) 
returns 
2020-10-25 03:00:00+01:00

while

pd.to_datetime('2020-10-25').tz_localize('Europe/Berlin') + pd.DateOffset(hours=3) 
returns 
Timestamp('2020-10-25 02:00:00+0100', tz='Europe/Berlin')
```


### Issue Description

Mismatch between the outputs. 

[Here](https://stackoverflow.com/questions/69364849/combine-first-at-dst-changing-day-fails/69365229?noredirect=1#comment122602688_69365229) is the stackoverflow post describing in detail the issue.

### Expected Behavior

Returning same datetime

### Installed Versions

<details>

INSTALLED VERSIONS
------------------
commit           : 73c68257545b5f8530b7044f56647bd2db92e2ba
python           : 3.9.4.final.0
python-bits      : 64
OS               : Windows
OS-release       : 10
Version          : 10.0.19041
machine          : AMD64
processor        : Intel64 Family 6 Model 165 Stepping 2, GenuineIntel
byteorder        : little
LC_ALL           : None
LANG             : None
LOCALE           : English_United States.1252

pandas           : 1.3.3
numpy            : 1.19.5
pytz             : 2021.1
dateutil         : 2.8.1
pip              : 21.2.4
setuptools       : 52.0.0.post20210125
Cython           : 0.29.23
pytest           : 6.2.3
hypothesis       : None
sphinx           : 4.0.1
blosc            : None
feather          : None
xlsxwriter       : 1.3.8
lxml.etree       : 4.6.3
html5lib         : 1.1
pymysql          : None
psycopg2         : None
jinja2           : 2.11.3
IPython          : 7.22.0
pandas_datareader: None
bs4              : 4.9.3
bottleneck       : 1.3.2
fsspec           : 0.9.0
fastparquet      : None
gcsfs            : None
matplotlib       : 3.3.4
numexpr          : 2.7.3
odfpy            : None
openpyxl         : 3.0.7
pandas_gbq       : None
pyarrow          : None
pyxlsb           : 1.0.8
s3fs             : None
scipy            : 1.6.2
sqlalchemy       : 1.4.7
tables           : None
tabulate         : None
xarray           : None
xlrd             : 2.0.1
xlwt             : 1.3.0
numba            : 0.53.1



</details>
