Alright, here is a working version.
Instead of the intervals manipulating the Grid, I have it manipulating the pagination control:
import dash_ag_grid as dag
from dash import Dash, html, dcc, Input, Output, no_update, callback, State
import pandas as pd
import dash_bootstrap_components as dbc
app = Dash(__name__, external_stylesheets=[dbc.themes.BOOTSTRAP])
df = pd.read_csv(
"https://raw.githubusercontent.com/plotly/datasets/master/ag-grid/olympic-winners.csv"
)
# basic columns definition with column defaults
columnDefs = [
{"field": "country"},
{"field": "year"},
{"field": "athlete"},
{"field": "sport"},
{"field": "total"},
]
app.layout = html.Div(
[
dcc.Interval(id='update', n_intervals=0, interval=1000 * 3),
dcc.Markdown(
"Example of custom pagination controls with Dash Bootstrap Components `dbc.Pagination`"
),
dbc.Pagination(
id="custom-pagination",
max_value=87,
first_last=True,
previous_next=True,
size="sm",
fully_expanded=False,
),
dag.AgGrid(
id="custom-pagination-grid",
columnDefs=columnDefs,
rowData=df.to_dict("records"),
columnSize="sizeToFit",
defaultColDef={"resizable": True, "sortable": True, "filter": True},
dashGridOptions={
"pagination": True,
"suppressPaginationPanel": True,
"suppressScrollOnNewData": True,
},
),
],
style={"margin": 20},
)
@callback(
Output("custom-pagination", "max_value"),
Input("custom-pagination-grid", "paginationInfo"),
)
def update_pagination_control(pagination_info):
if pagination_info is None:
return no_update
return pagination_info["totalPages"]
@callback(
Output("custom-pagination-grid", "paginationGoTo"),
Input("custom-pagination", "active_page"),
prevent_initial_call=True
)
def goto_page(n):
if n is None or n == 1:
return "first"
# grid pagination starts at zero
return n - 1
@app.callback(
Output("custom-pagination", "active_page"),
Input('update', 'n_intervals'),
State("custom-pagination-grid", "paginationInfo"),
prevent_initial_call=True
)
def auto_pagination(timer, pagination_info):
total_pages = pagination_info["totalPages"]
current_page = pagination_info["currentPage"]
if timer % 2 == 0:
if current_page + 1 == total_pages:
return 0 + 1
else:
return current_page + 2
else:
return no_update
if __name__ == "__main__":
app.run(debug=True)
The tricky part is the grid starts at 0 while the dbc pagination starts at 1, thus I had to shift them. 
